The present invention relates in general to brakes and, more particularly, to disk brakes, particularly but not exclusively for vehicles. More specifically, the invention relates to a safety device for brake-pad support pins or bolts.
In disk brakes, particularly of the type fitted in vehicles, the pads which bear linings of friction material are supported within a so-called caliper body with the ability to move away from and towards the disk surface or braking band when they are acted on by hydraulic or pneumatic cylinder-piston units so as to be able to perform the braking action when required. Pins or bolts are used for supporting the pads in the caliper body and extend through the caliper body and through through-holes provided in the pads, their ends engaging in seats provided for the purpose in the caliper body. These support pins are supported by the caliper body so as to be removable axially since they have to be removed to enable the pads to be replaced when they are worn. However, the pins must be prevented from slipping out of the caliper body accidentally when the vehicle is in motion since this would result in the correct operative positioning of the pads no longer being ensured.
According to a known solution, the pins supporting the pads are prevented from slipping out of the caliper body by means of safety split pins mounted substantially in the vicinity of one end of each support pin, each split pin having a first limb which can be fitted in a through-hole formed for the purpose in the support pin, transverse the axis thereof. The other limb of each split pin has a portion which is shaped to form an arc with a radius substantially corresponding to that of the support pin and which grips the support pin, when the split pin is mounted, to prevent the first limb from undesirably slipping out of the through-hole in the support pin.
Moreover, the caliper body has recesses which leave the support pins exposed in the region of the transverse through-holes formed therein and the split pins are housed in these recesses. The split pins thus come into abutment with the walls of the recesses, preventing the support pins from slipping out.
Clearly, once the split pins are fitted in the respective support pins, they are also fixed for rotation with the support pins about the axes thereof. When the vehicle is in motion and, in particular, each time braking takes place, vibrations are produced and are propagated to the pins supporting the pads. These support pins, which are housed substantially loosely in the caliper body, vibrate and tend to rotate about their own axes, also causing the respective split pins to rotate.
To prevent the rotation of the support pins causing the split pins to strike against portions of the caliper body, for example, against the edges of the recesses housing the split pins, the eyes of the split pins are bent so as to lie in a plane perpendicular to the plane in which their two limbs lie. When the split pins are fitted, their eyes thus lie substantially on an outer surface of the caliper body in the vicinity of the edges of the respective recesses.
This solution may have disadvantages since the rotations of the support pin about its own axis are transmitted to the split pins, causing them to knock or at least rub against the caliper body. In time, the split pins could deteriorate or break. Any breakage of the split pins is an event which could have disastrous consequences and is absolutely to be avoided.
The object of the present invention is therefore to provide a safety device for brake-pad support pins which does not have the above-mentioned disadvantages.
According to the present invention, this object has been achieved by a retainer clip for brake-pad support pins. In one embodiment, the brake-pad support pin is supported removably by a caliper element which is intended to hold the pads. The retainer clip is associated removably with at least one support pin to prevent the support pin from slipping out of the caliper element. The retainer clip of this embodiment comprises, for each support pin, at least one respective clip with an eye which can be mounted astride the support pin wherein the eye extends around the support pin, and in that the at least one support pin has abutment means for preventing relative axial sliding of the clip on the support pin in at least one direction, preventing slipping of the support pin out of the caliper element.